Sample introduction device
Patent 7157056 Issued on January 2, 2007. Estimated Expiration Date: 
September 10, 2022. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
September 10, 2022. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2761417 3872730 Integral analytical element Integral element for analysis of liquids Multi-layer chemical analytical materials Autosampler mechanism Unified test means for ion determination Ion test means having a hydrophilic carrier matrix Ion test means having a porous carrier matrix Test device, method of manufacturing same and method of determining a component in a sample InventorAssigneeApplicationNo. 10238946 filed on 09/10/2002US Classes:422/100, Pipette or other volumetric fluid transfer means73/64.56, Sampler, constituent separation, sample handling, or sample preparation73/61.59, With detail of sampling, sample handling, or sample preparation73/61.55, Including sampling, sample handling, or sample preparation141/329With puncturing connecting meansExaminersPrimary: Warden, JillAssistant: Levkovich, Natalia Attorney, Agent or FirmForeign Patent References
International ClassB01L 3/02DescriptionBACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to sample handling devices, and more particularly to a device for introducing samples into sample chambers of a test instrument. 2. Background Information Chemical analysis of liquids, including biological liquids such as blood, plasma or urine is often desirable or necessary. Sensors that utilize various analytical elements to facilitate liquid analysis are known. These elements have oftenincluded components which specifically react to a substance or characteristic under analysis, termed analyte herein. These components, upon contacting a liquid sample containing the analyte, effect formation of a colored or fluorescent material oranother detectable response to the presence of the analyte. In this regard, analytical elements such as disclosed in commonly assigned U.S. patent application Ser. No. 08/617,714 (hereinafter, the '714 Patent Application) have been provided. Analytical elements of this type are adapted for use within asample chamber of an optical sensor assembly. In operation, a fluid sample of unknown analyte content (an "unknown sample") is tested by introducing the sample into the sample chamber where it contacts the analytical element. Any change in the opticalcharacteristics of the analytical element are observed to thus determine characteristics of the analyte of interest in the sample. An example of a sensor assembly of this type is disclosed in commonly assigned U.S. patent application Ser. No.09/010,096, entitled "OPTICAL SENSOR AND METHOD OF OPERATION" (hereinafter referred to as the "OPTICAL SENSOR" patent application) which is hereby incorporated by reference in its entirety, herein. The sample chambers of this and similar types of sensorassemblies are generally incorporated into multiple use clinical instrumentation which utilize a sample introduction device, including an aspiration probe, to withdraw a sample, such as blood or other fluid, from a syringe or the like and transfer thesample into the sample chamber. An example of instrumentation that utilizes an aspiration probe to withdraw a sample is disclosed in commonly assigned U.S. patent application Ser. No. 60/006,741, entitled "MULTIFUNCTION VALVE" filed on Nov. 2, 1995. In this type of instrumentation, once the tip of the aspiration probe is immersed within the syringe, a suction pump draws blood through the probe and into the instrument. As the blood sample flows from the syringe, its volume is replaced by airthat passes through an opening in the coupling between the syringe and the instrument, and through an annular space between the probe and the opening of the syringe. While multiple use instruments that draw blood in this manner may operate satisfactorily in many applications, they present some difficulties. In particular, the sample introduction device, including the inside of the aspiration probe, must beroutinely cleaned between samples to prevent clogs and cross contamination of the samples. Although blood gas sample syringes are treated with an anti-coagulant, blood samples often contain micro-clots which can block the narrow flow passages of sampleintroduction devices of analytical instrumentation. In many current blood gas analyzers, such as the Rapidpoint 400 sold by Bayer Corporation of Medfield, Mass., problems associated with these clots are minimized by providing the inlet of the sampleaspiration probe with the smallest diameter of the entire sample flow path through the sample introduction device. If a clog does occur, it is likely to be at the tip of the probe and can be cleared by wiping or flushing. However, the inclusion ofprobe washing facilities complicates the fluidics of a clinical analyzer. Moreover, the washing sequence is time consuming and disadvantageously reduces the availability of the instrument for sample analysis. Such delay may be particularlydisadvantageous in some operating environments such as, for example, in critical care facilities. Further, discarded wash fluid or reagent comprises a significant portion of the waste generated by such conventional analytical instrumentation. This waste is classified as biohazardous and thus disposal thereof is relatively expensive, both ineconomic and environmental terms. This waste also poses a potential health risk to health care workers and those who may otherwise come into contact with the waste during or after disposal. Thus, a need exists for an improved sample introduction device that reduces the need for washing between samples to reduce the amount of reagent required therefor and that otherwise overcomes the drawbacks of the prior art. SUMMARY OF THE INVENTION According to an embodiment of the present invention, a sample introduction device is adapted for introducing a sample into a sample chamber of a sensor from a container maintained in fluid communicating relationship therewith. The sampleintroduction device comprises a probe of substantially tubular construction, having a first end adapted to extend into the container and a second end adapted for connection to a material volume supply. The probe is adapted to inject a predeterminedvolume of gas into the container to displace a predetermined volume of the sample from the container into the sample chamber. In a variation of the first aspect of the present invention, a test apparatus is provided for determining analyte content of a sample. The test apparatus comprises the sample introduction device of the first aspect of the invention. Inaddition, the sensor has at least one sample chamber and the container is adapted for being maintained in fluid communicating relationship therewith. In a second aspect of the present invention, a method is provided for introducing a sample into a sample chamber. This method comprises the steps of maintaining a sample container in fluid communicating relationship with the sample chamber; andinjecting a predetermined volume of gas into the sample container, wherein a predetermined volume of a sample disposed within the sample container is displaced by the gas from the container into the sample chamber. In a variation of this second aspect of the invention, a method of operating a sensor is provided. This method comprises the steps of introducing a sample into a single use sample chamber as set forth in the second aspect; measuring predetermined parameters of the sample disposed in the single use sample chamber; and discarding the sensor with sample fluid disposed within the sample chamber. The above and other features and advantages of this invention will be more readily apparent from a reading of the following detailed description of various aspects of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, with portions thereof in phantom and portions thereof broken away, of a representative application utilizing an embodiment of the present invention; FIG. 2 is a cross-sectional elevational view of an other similar representative application utilizing an embodiment of the present invention, during a step in the operation thereof; FIG. 3 is a view similar to that of FIG. 2, during another step in the operation of the present invention; FIG. 4 is a view similar to those of FIGS. 2 and 3, during a further step in the operation of the present invention; FIG. 5 is a view similar to those of FIGS. 2 4, during a still further step in the operation of the present invention; and FIG. 6 is a view similar to those of FIGS. 2 5, during a yet further step in the operation of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the figures set forth in the accompanying Drawings, illustrative embodiments of the present invention will be described in detail hereinbelow. For clarity of exposition, like features shown in the accompanying drawings shall beindicated with like reference numerals and similar features shown for example in alternate embodiments in the drawings, shall be indicated with similar reference numerals. Briefly described, as shown in the Figs., the present invention includes a sample introduction device 10 (FIG. 2) adapted for introducing a liquid sample or test sample 12 (FIG. 2) from a container or syringe 14 to a sample chamber 116 of asensor assembly 118 for analysis. Device 10 includes a Luer fitting or coupling 20 (FIG. 2) adapted to mate an outlet 22 of the container in a concentric orientation with an input aperture 24 of the sample chamber. A tubular probe 26 is adapted toextend in fluid tight engagement through backing web 38 of sensor assembly 18 in (FIG. 1) or sensor assembly 118 in (FIG. 2), for concentric placement with both outlet 22 and inlet aperture 24 with a first end 28 thereof extending into the syringe. Adistal end 29 is adapted for attachment to an air supply (not shown) as will be discussed hereinafter. Probe 26 has a predetermined diameter sufficient to provide an annular clearance or opening 30 (FIGS. 1, 3 and 6) between the probe and each of outlet22 and inlet aperture 24. The probe is adapted to inject a predetermined volume of a material 32, preferably a gas such as air (FIGS. 4 and 5) therein. The gas serves to displace a predetermined volume of sample 12 from container 14 through annularclearance 30 to enable the sample to pass therethrough into sample chamber 16 or 116. The combination of mating syringe 14 directly to sensor assembly 18 or 118 and injecting air into the syringe through probe 26 to displace the sample therefrom, rather than drawing the sample into the probe, serves to advantageously eliminate theneed for washing the interior of the probe. Moreover, the use of the present invention in combination with the aforementioned multiple single use sensor assembly 18 or 118 advantageously provides "hands-off" sample introduction, substantially reducesthe need for probe and sample chamber washing, to in turn, reduce use of wash reagents. Sample introduction device 10 of the present invention is suitable for use in many types of analytical instrumentation. It is particularly useful in the critical care environment for the anaerobic withdrawal of small volumes of arterial bloodfrom a sample collection syringe. Throughout this disclosure, the term "analyte" shall refer to any substance, compound, or characteristic such as, for example, pH, oxygen, carbon dioxide and ions, among others, capable of detection and/or measurement relative to a liquid sample. Similarly, the term "concentration" shall refer to the level or degree to which an analyte is present in a sample. The term "tubular" shall refer to an elongated, hollow member of substantially any transverse cross-sectional geometry, including, but notlimited to circular, square or other polygonal geometry. Turning now to the drawings in detail, in FIG. 1 portions of a sample introduction device 10 (FIG. 2) are shown in a representative application. Sensor assembly 18 includes a series of sample chambers 16, each of which include an input aperture24 and an output aperture 25. Syringe 14 is disposed in operative engagement with an input aperture 24 of one of the sample chambers 16. Probe 26 is shown in its fully inserted position concentrically disposed with both input aperture 24 and outlet 22of syringe 14, with first end 28 thereof extending into syringe 14. Luer fitting 20 (FIG. 2), including the fluid pathway between syringe 14 and input aperture 24 of the sample chamber have been omitted from FIG. 1 for clarity. As also shown, sensor assembly 18 comprises a multiple single use optical sensor of the type disclosed in the above-referenced "OPTICAL SENSOR" patent application. Alternatively, however, the present invention may be utilized in combination withsubstantially any type of sample chamber, including single and multiple use sample chambers, in addition to the multiple single use chambers shown. In this regard, the present invention may be effectively utilized in combination with sample chambers ofvarious types of sensors in addition to the optical sensors shown, including, for example, chemical, electrical and/or electrochemical sensors. Referring now to FIG. 2, a sample 12, such as, for example, blood, urine or other fluid, is maintained within syringe 14. Outlet 22 of the syringe is matingly engaged with a Luer fitting 20 of substantially conventional construction. Luerfitting 20 is sized and shaped to receive and maintain outlet 22 in fluid communicating relation with input aperture 24 of sample chamber 116. In a preferred embodiment, as shown, the Luer fitting is adapted to provide a fluid tight seal with outlet 22to prevent leakage of sample 12 during sample introduction as will be discussed hereinafter. As also shown, Luer fitting 20 is preferably disposed integrally with a sensor assembly 118, in concentric alignment with an input aperture 24. Thus, whenfully engaged with fitting 20, outlet 22 is preferably maintained in concentric orientation with the input aperture 24. Sensor assembly 118 is substantially similar to sensor assembly 18 shown in FIG. 1, with the exception that each sample chamber 116 thereof includes an integral waste receptacle 34 which will be discussed in greater detail hereinafter. A probeaperture 36 is disposed concentrically with input aperture 24, on an opposite side of sensor assembly 118 therefrom. Thus, as shown, probe aperture 36 is disposed in substrate or backing web 38 of sensor assembly 118. The probe aperture is sized andshaped to provide a substantially fluid tight seal with probe 26 when inserted therein, as will be discussed hereinafter. Thus, in a preferred embodiment, web 38 is fabricated as a flexible film as disclosed in the above referenced "OPTICAL SENSOR"patent application and probe aperture 36 is sized and shaped to be slightly smaller than, to provide an interference fit with, probe 26 to thus form the fluid tight seal therebetween. As shown, probe 26 is maintained in a ready or retracted position relative sensor assembly 118 and syringe 14 by a fixture or support means (not shown) of a test apparatus (also not shown) within which the present invention is incorporated. Thetest apparatus also includes a series of emitter/receptor heads or optical reader heads 40 maintained in alignment with each of a series of sensor stripes 42 (FIG. 1) of the sensor assembly. Emitter/receptor heads 40 are thus adapted to measure responseof sensor stripes 42 to the presence of analytes in sample 12 in a manner set forth in the above referenced "OPTICAL SENSOR" patent application, and as will be discussed in greater detail hereinafter with respect to the operation of the presentinvention. In this regard, moreover, the specific operations of sample introduction device 10, including the operation of emitter/receptor heads 40, operation of probe 26 and the supply of material 32 are preferably controlled by a logic device orcontrol module (not shown) such as a computer incorporated into the test apparatus in a manner familiar to those skilled in the art. The orientation of sample introduction device 10, as shown, with outlet 22 matingly engaged with fitting 20 and probe 26 in its ready position, comprises an initial step in the operation of the present invention. Referring now to FIG. 3, in a subsequent step in the operation of the present invention, probe 26 is inserted into probe aperture 36, input aperture 24 and outlet 22 until first end 28 is disposed within sample 12. As shown, probe 26 ispreferably disposed concentrically with apertures 36 and 24, as well as with outlet 22. The volume of the probe inserted therein will displace a predetermined, relatively small volume of sample 12 into annular opening 30 within outlet 22 as shown. Turning now to FIG. 4, the next step in the operation of the present invention is to supply a predetermined volume of material 32 to distal end 29 of probe 26. Material 32 may be substantially any flowable substance, i.e. an immiscible liquid, apaste-like material such as silicone grease, solid beads or granules, or gas. The particular material selected is preferably inert. As used herein, the term `inert` is defined as being substantially non-reactive with the sample. Similarly, the term`inert gas` is defined as a gas that only changes the partial pressure through its fractional equivalence or when it is dissolved in the sample, as opposed to a chemically reactive gas such as a chloride which may rapidly react chemically with elementsin the sample to form HCL. Although a non-reactive material is preferred, one skilled in the art will recognize that non-reactivity with the sample is important only to the degree that sample remaining in the sample container is affected. The sample being analyzed isdisposed within the sample chamber and is not in direct contact with the material 32. Thus, if only one sample is to be taken from sample container, a reactive material may be utilized. In the case of a blood sample, the presence of any gas phase, forexample, will affect the levels of some analytes (particularly dissolved oxygen). This is a potential problem with any sampling method which draws a sample from a fixed volume. From a practical viewpoint the degradation from an inert bubble such as airin a blood sample is relatively slow, and if the sample is to be used for multiple tests, the air bubbles are preferably expelled from the syringe immediately after sampling. As discussed hereinabove, material 32 is preferably an inert gas. A particular gas is chosen based on convenience and availability. The gas may comprise any gas which does not affect the sample, or a combination of such gases provided by anyconvenient gas supply, such as, for example, a commercially available compressed gas canister. In this regard, when the sample is whole blood, examples of suitable gases include air, nitrogen and propane. In a preferred embodiment, the gas comprisesair and is provided by either a gas canister or by conventional pump or compressor means (not shown). As shown, once the supply of gas is initiated, a bubble of gas 32 is formed at first end 28 of probe 26. Sample 12 is displaced thereby and as shown,begins to fill sample chamber 116. Optical reader heads 40, or alternatively, additional optical sensors (not shown), detect presence of sample 12 in the sample chamber and also determine the integrity (absence of bubbles) of the sample disposed withinthe sample chamber. As shown in FIG. 5, once reader heads 40 (or the alternative optical sensors) detect sample chamber 116 is substantially filled by sample 12, the supply of gas 32 is terminated. Alternatively, a predetermined fixed volume of gas is injected. Optical reader heads 40 are then operated in the manner set forth in the above-reference "OPTICAL SENSOR" patent application to test, or collect information, such as, for example, analyte concentration within sample 12, from each portion of the sensorstripes 42 (FIG. 1) disposed within sample chamber 116. Turning now to FIG. 6, once testing of sample 12 is complete, probe 26 is withdrawn from syringe 14. As the probe moves through probe aperture 36, the aforementioned fluid tight engagement with probe 26 serves to effectively wipe any residualportion of sample 12 from the exterior of the probe. This wiping action advantageously cleans probe 26 without the need to flush the interior thereof with wash reagents, as would otherwise be necessary in the event samples were passed through theinterior of the probe as in the aforementioned prior art devices. In a preferred embodiment as shown, additional gas is supplied to the probe once the probe has been withdrawn from the sample fluid disposed within the syringe, and before first end 28 of the probe is withdrawn from probe aperture 36. Thisadditional gas serves to push sample 12 out of sample chamber 116 and into waste receptacle 34. In this manner, sample 12 may simply remain in the sensor assembly to be discarded along with sensor assembly 118 once all of the sample chambers thereofhave been utilized, as will be discussed hereinafter. Alternatively, in the aforementioned embodiment that utilizes a sample chamber 16 (FIG. 1) without a waste receptacle, probe withdrawal may be implemented without the additional supply of gas, toleave sample 12 in the sample chamber. Thus, in both these embodiments, the sample 12 may simply remain in the sensor assembly and be subsequently discarded along with sensor assembly 18 or 118 once all of the sample chambers thereof have been utilized,as will be discussed hereinafter. In a further alternative, rather than leave sample 12 within the sensor assembly, the aforementioned supply of additional gas may be utilized to push sample 12 out of output aperture 25 (FIG. 1). The sample may then be collected by any suitablecollection means (not shown) familiar to those skilled in the art. The final step in the operation of the present invention is to completely withdraw probe 26 into its ready position as shown in FIG. 2, whereupon syringe 14 may be removed and a fresh sample chamber 16 or 116 indexed into sensing contact withemitter/receptor heads 40 for subsequent testing in the manner described hereinabove. Thus, as shown and described hereinabove, the present invention serves to effectively reverse the flow path of prior art instrumentation which, as discussed hereinabove, use an aspiration probe to withdraw a blood sample from a syringe. In thismanner, rather than removing a sample and letting air be drawn into the syringe to replace the volume of the withdrawn sample, the present invention pumps an air bubble from probe 26 into syringe 14, displacing a volume of blood sample 12, which flowsthrough the syringe/probe annular opening 30, into the instrument Luer coupling 20 and subsequently into sample chamber 16 or 116. The benefit of this mode of operation is that blood does not enter the inside of probe 26, and thus permits cleaning bywiping the exterior of the probe, rather than washing the interior thereof. Advantageously, this aspect serves to reduce time, safety and waste relative to the prior art. It should be understood that although a gas bubble is used for the displacement volume in the prefered embodiment, any material (e.g. water, a liquid or a flowable paste-like substance such as silicone grease) which can be dispensed through theprobe and will displace the sample material, may be used if contamination in re-sampling is not an issue. Moreover, use of the present invention in combination with a single use sample chamber nominally eliminates the need for sample chamber washing and simplifies disposal since the sample can remain in the sample chamber after testing to besubsequently discarded therewith as a single unit. The present invention thus effectively provides a sample handling system that substantially reduces the need for wash reagent, waste containers to receive the used wash reagent and samples, and timeconsuming wash sequences. The foregoing description is intended primarily for purposes of illustration. Although the invention has been shown and described with respect to an exemplary embodiment thereof, it should be understood by those skilled in the art that theforegoing and various other changes, omissions, and additions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention. * * * * * |
